We offer a large selection of Flat Mailers. You can search many types of Dura-Bag Flat and Expandable Mailers, Eco-Shipper Flat and Expandable Mailers, Kraft Jiffy Rigi Bag Self and Tamper Evident Security Envelopes. Kraft Dura - Bag Expandable Reinforced Mailer is fiberglass strands laminated to kraft paper create tough mailers that resist tears and punctures. Lightweight to reduce shipping cost. Eco-Shipper Flat Peel-and-Seal Mailer is a tough, non-padded shipper used to protect paper documents, clothing, and parts. They are superior tear and moisture resistant. Peel-and-seal strip ensures secure closure.